Water travels upward from roots to leaves through narrow xylem tubes in tall trees. Which combination of properties drives this transport?

Core Concept

Hydrogen bonding makes neighboring water molecules cling together, so evaporation at the leaf surface pulls the entire liquid column upward without letting it snap. Adhesion between water and the charged cellulose walls of xylem counteracts gravity's tendency to drain the column back down. Together these forces sustain a continuous stream under tension from root to leaf, a mechanism called the cohesion-tension process. Capillary rise in thin glass tubes demonstrates the same paired forces on a laboratory scale.